def bonus(sales):
    if sales<=10000:
        return 5000
    elif sales>10000 and sales<=20000:
        return 5000+sales*0.10
    elif sales>20000 and sales<=50000:
        return 5000+sales*0.15
    elif sales>50000 and sales<=100000:
        return 5000+sales*0.20
    else:
        return 5000+sales*0.25

sales=eval(input())
print("%.2f"%bonus(sales))
